aspect ratio

learning/shapes/box.frag

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+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2 u_resolution;
+uniform vec2 u_mouse;
+uniform float u_time;
+
+#define PI 3.14159265359
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  vec3 color = vec3(0.0,0.0,0.0);
+
+
+  //draw box
+  //float left = step(0.1,st.x); // everything > 0.1 = 1.0
+  //float bottom = step(0.1,st.y); // everything > 0.1 = 1.0
+  //float right = 1.0-step(0.9,st.x);
+  //float top = 1.0-step(0.9,st.y);
+  //color = vec3(left*bottom*top*right);
+  vec2 bottom_left = step(vec2(0.1),st); // does the same as previous code but passes vec2's to get both
+  vec2 top_right = vec2(1.0)-step(vec2(0.9),st);
+  color = vec3(bottom_left.x * bottom_left.y * top_right.x * top_right.y);
+  
+  gl_FragColor = vec4(color, 1.0);
+}

learning/shapes/circle.frag

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+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2 u_resolution;
+uniform vec2 u_mouse;
+uniform float u_time;
+
+#define PI 3.14159265359
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  // vec3 color = vec3(0.0,0.0,0.0);
+
+  float pct = distance(gl_FragCoord.xy, (vec2(0.5)*u_resolution)) // find a way to make this a circle even when non 1:1 aspect ratio
+  vec3 color = vec3(pct);
+  gl_FragColor = vec4(color, 1.0);
+}

learning/shapes/main.frag

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+
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2    u_resolution;
+uniform vec2    u_mouse;
+uniform float   u_time;
+
+varying vec2    v_texcoord;
+
+void main(void) {
+    vec4 color = vec4(vec3(0.0), 1.0);
+    vec2 pixel = 1.0/u_resolution.xy;
+    vec2 st = gl_FragCoord.xy * pixel;
+    vec2 uv = v_texcoord;
+
+    color.rgb = vec3(st.x,st.y,abs(sin(u_time)));
+    
+    gl_FragColor = color;
+}